JP2013215591A - Ophthalmic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmic apparatus for, when the alignment based on a pupil center and a position where a tomographic image can be imaged in an excellent position are different depending on a subject, continuously performing auto-alignment in the position.SOLUTION: An initial position adjustment is performed after an initial adjustment target position on an obtained anterior eye image is matched with the optical axis of a measurement optical system, the measurement optical system is moved by a movement amount corresponding to a movement instruction when the instruction of the initial adjustment target position is received, and the initial adjustment target position on the anterior eye image is changed to the position after the movement to perform a position adjustment again.

Description

  The present invention relates to an ophthalmologic apparatus used for capturing a fundus surface image and a tomographic image of a subject eye.

  In recent years, an apparatus using an optical coherence tomography (OCT: Optical Coherence Tomography) that captures a tomographic image using interference by low-coherence light (hereinafter also referred to as an OCT apparatus) has been put into practical use. This is because a tomographic image can be taken with a resolution about the wavelength of the light incident on the inspection object, so that a tomographic image of the inspection object can be obtained with a high resolution. The OCT apparatus is particularly useful as an ophthalmologic apparatus for obtaining a tomographic image of the retina located at the fundus.

  On the other hand, in general, in an ophthalmologic apparatus regardless of fundus examination, it is important to accurately align an examination part (mainly a measurement optical system) of the apparatus with an eye to be examined for imaging.

  In Patent Document 1, when the eyeball is turbid, such as a cataract, the measurement unit is driven with respect to the subject's eye, and the light returning from the fundus at each position is received by the sensor. An eye refractive power measurement device that predicts whether measurement can be performed well and performs measurement at a favorable position is described.

  Patent Document 2 describes an optical image measurement device that is an OCT device that automatically captures a tomographic image when the alignment is good.

JP 2000-245698 A JP 2010-181172 A

  Here, in the case where the apparatus of Patent Document 1 is applied to an OCT apparatus, since various inspections are performed and the inspection time is relatively long, the optimum position is automatically determined each time continuous fixation movements occur. There is a problem that it is necessary to search and the alignment time becomes long.

  In Patent Document 2, although mention is made of auto-alignment of an eye to be examined, there is no description of a specific configuration.

  Here, continuous auto-alignment is desired in an OCT apparatus having a relatively long inspection time per person.

In many cases, the alignment with respect to the eye to be examined is performed by detecting the pupil center position of the anterior eye part and aligning the optical axis of the measurement part at that position, regardless of whether it is manual or automatic. However, the tomographic image of the fundus may become dark depending on the eye to be examined. At that time, in the manual OCT apparatus, the examiner needs to make fine adjustments to make the fundus tomographic image favorable.
From this point, there is no OCT apparatus that continuously performs auto-alignment, and there is nothing that continuously obtains better images.

In view of the above problems, the ophthalmologic apparatus of the present invention is a tomographic image of the subject eye acquired based on the head unit including a measurement optical system that guides the return light from the illuminated subject eye to the light receiving unit And a position changing means for changing a relative position between the head portion and the eye to be examined based on the inclination .

  In the fundus examination apparatus of the present invention, it is possible to continuously perform automatic alignment to a position where a good tomographic layer can be imaged. From the point of view of the examiner, the use is simple, and from the point of view of the subject, the examination time is shortened and the burden is reduced.

FIG. 6 is a flowchart for explaining image capturing in the first and second embodiments. FIG. 6 is a flowchart for explaining image capturing in the first and second embodiments. It is a figure explaining the fundus examination device in Examples 1 and 2. It is a figure explaining the anterior eye image in alignment in Example 1 and 2. FIG. 6 is a diagram illustrating a preview image of a tomographic image during alignment in Examples 1 and 2. FIG. It is a figure explaining the to-be-examined eye and the observation light beam in Example 1 and 2. FIG. It is a figure explaining the screen for alignment in Example 1 and 2. FIG.

[Example 1]
The fundus examination apparatus according to the present embodiment is an OCT apparatus having an auto-alignment function, which can automatically determine a position where a good tomographic image can be captured and can continuously perform auto-alignment at that position. It is.

(Schematic configuration of the device)
A schematic configuration of the fundus examination apparatus according to the present embodiment will be described with reference to FIG.
2A is a side view of the ophthalmologic apparatus, 200 is an ophthalmologic apparatus that is a fundus examination apparatus, and 900 is an optical that is a measurement optical system for capturing an anterior ocular image, a two-dimensional image of the fundus, and a tomographic image. A head 950 is a stage unit that is a moving unit that can move the optical head in the xyz direction in the drawing by using a motor shown in the figure. Reference numeral 951 denotes a base unit incorporating a spectroscope described later.

  Reference numeral 925 denotes a personal computer that also serves as a movement control unit that controls the movement of the stage unit, and functions as an apparatus control unit that performs tomographic image configuration and the like along with the control of the stage unit. A hard disk 926 also serves as a subject information storage unit and stores a program for tomographic imaging. A monitor 928 is a display unit, and an input unit 929 is an instruction unit for instructing a personal computer, and specifically includes a keyboard and a mouse. Reference numeral 323 denotes a chin stand, which fixes the subject's chin and forehead, thereby urging the subject's eyes (the subject's eyes) to be fixed.

(Configuration of measurement optical system and spectrometer)
The configuration of the measurement optical system and the spectroscope of this example will be described with reference to FIG.
First, the inside of the optical head 900 will be described. An objective lens 135-1 is installed facing the eye 107 to be inspected, and the optical path 351 of the OCT optical system, fundus observation and fixation lamp are placed on the optical axis by the first dichroic mirror 132-1 and the second dichroic mirror 132-2. The optical path 352 is branched into the optical path 352 for anterior eye and the optical path 353 for anterior eye observation for each wavelength band.

  The optical path 352 is further branched for each wavelength band by the third dichroic mirror 132-3 to the optical path to the fundus observation CCD 172 and the fixation lamp 191. Here, reference numerals 135-3 and 135-4 denote lenses, and 135-3 is driven by a motor (not shown) for focusing for fixation light and fundus observation. The CCD 172 has sensitivity at the wavelength of the illumination light for fundus observation shown in the figure, specifically, around 780 nm. On the other hand, the fixation lamp 191 generates visible light to promote fixation of the subject.

  In the optical path 353, 135-2 is a lens, and 171 is an infrared CCD for anterior eye observation. The CCD 171 has sensitivity at a wavelength of illumination light for anterior eye observation (not shown), specifically, around 970 nm.

The optical path 351 forms an OCT optical system as described above, and is used to capture a tomographic image of the fundus of the eye 107 to be examined. More specifically, an interference signal for forming a tomographic image is obtained. Reference numeral 134 denotes an XY scanner for scanning light on the fundus. The XY scanner 134 is illustrated as a single mirror, but performs scanning in the XY biaxial directions. Reference numerals 135-5 and 135-6 denote lenses, and the lens 135-5 is for focusing the light from the light source 101 emitted from the fiber 131-2 connected to the optical coupler 131 on the fundus 107. It is driven by a motor (not shown). By this focusing, the light from the fundus 107 is simultaneously spotted and incident on the tip of the fiber 131-2.

Next, the configuration of the optical path from the light source 101, the reference optical system, and the spectroscope will be described.
Reference numeral 101 denotes a light source, 132-4 denotes a mirror, 115 denotes dispersion compensation glass, 131 denotes the optical coupler described above, 131-1 to 4 denote a single mode optical fiber connected to the optical coupler, and 135-7 denotes a lens. , 180 is a spectroscope.

The Michelson interference system is configured by these configurations. The light emitted from the light source 101 is split through the optical fiber 131-1, through the optical coupler 131, into measurement light through the optical fiber 131-2 and reference light through the optical fiber 131-3.
The measurement light is irradiated onto the fundus of the eye 107 to be observed through the OCT optical system optical path described above, and reaches the optical coupler 131 through the same optical path due to reflection and scattering by the retina.

  On the other hand, the reference light reaches the mirror 132-4 and is reflected through the optical fiber 131-3, the lens 135-7, and the dispersion compensation glass 115 inserted in order to match the dispersion of the measurement light and the reference light. Then, it returns on the same optical path and reaches the optical coupler 131.

The measurement light and the reference light are combined by the optical coupler 131 to become combined light (interference light). Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light are substantially the same. The mirror 132-4 is held so as to be adjustable in the optical axis direction by a motor and a driving mechanism (not shown), and the optical path length of the reference light can be adjusted to the optical path length of the measurement light that changes depending on the eye 107 to be examined. The interference light is guided to the spectroscope 180 via the optical fiber 131-4. Reference numeral 139-1 denotes a measurement light side polarization adjusting unit provided in the optical fiber 131-2.
Reference numeral 139-2 denotes a reference light side polarization adjusting unit provided in the optical fiber 131-3. These polarization adjusters have several parts that have the optical fiber routed in a loop shape, and rotate the loop-shaped part around the longitudinal direction of the fiber to twist the fiber and reference the measurement light It is possible to adjust and adjust the polarization state of light. In this apparatus, the polarization states of the measurement light and the reference light are adjusted and fixed in advance.

The spectroscope 180 includes lenses 135-8 and 135-9, a diffraction grating 181, and a line sensor 182.
The interference light emitted from the optical fiber 131-4 becomes parallel light via the lens 135-8, is then split by the diffraction grating 181, and is imaged on the line sensor 182 by the lens 135-9.

  Next, the periphery of the light source 101 will be described. The light source 101 is an SLD (Super Luminescent Diode) which is a typical low coherent light source. The center wavelength is 855 nm and the wavelength bandwidth is about 100 nm. Here, the bandwidth is an important parameter because it affects the resolution of the obtained tomographic image in the optical axis direction. Further, although the SLD is selected here as the type of light source, it is only necessary to emit low-coherent light, and ASE (Amplified Spontaneous Emission) or the like can also be used. In view of measuring the eye, the center wavelength is preferably near infrared light. Moreover, since the center wavelength affects the lateral resolution of the obtained tomographic image, it is desirable that the center wavelength be as short as possible. For both reasons, the center wavelength was set to 855 nm.

  In this embodiment, a Michelson interferometer is used as an interferometer, but a Mach-Zehnder interferometer may be used. It is desirable to use a Mach-Zehnder interferometer when the light amount difference is large according to the light amount difference between the measurement light and the reference light, and a Michelson interferometer when the light amount difference is relatively small.

(Tomographic imaging method)
A tomographic image capturing method using the fundus examination apparatus 200 will be described. The fundus examination apparatus 200 can take a tomographic image of a desired site on the fundus of the eye 107 to be examined by controlling the XY scanner 134.

First, the measurement light is scanned in the x direction in the figure, and information on a predetermined number of images is captured by the line sensor 182 from the imaging range in the x direction on the fundus. A luminance distribution on the line sensor 182 obtained at a certain position in the x direction is subjected to FFT, and the linear luminance distribution obtained by the FFT is converted into density or color information so as to be displayed on the monitor 928 is called an A scan image . A two-dimensional image in which the plurality of A-scan images are arranged is referred to as a B-scan image. After imaging a plurality of A scan images for constructing one B scan image, the scan position in the y direction is moved and the scan in the x direction is performed again to obtain a plurality of B scan images.
By displaying a plurality of B-scan images or a three-dimensional tomographic image constructed from a plurality of B-scan images on the monitor 928, the examiner can use it for diagnosis of the eye to be examined.

(Tomographic imaging flow)
The imaging flowchart shown in FIG. 1A will be described in the order of steps.
In step 1001, imaging is started. An imaging program is executed by the personal computer 925 to activate an imaging screen on the monitor 928. At the same time, the XY scanner 134 is operated. The process proceeds to step 1002 automatically.

  In step 1002, a patient information input screen is displayed on the monitor 928, and the examiner inputs patient information if the patient is selected or is the first visit. The operation proceeds to step 1003 by an operation by the examiner (such as clicking an OK button displayed on the patient information input screen with a mouse).

Step 1003 displays an examination parameter selection screen on the monitor, and the examiner uses the left and right sides of the subject's eye as an examination parameter, in which range tomographic imaging is performed, how many tomographic images are taken, and the A scan included in the B scan image. Set the number of images. Note that settings related to tomographic image capturing are referred to as scan patterns. Then, the process proceeds to step 1004 by an operation by the examiner (such as clicking the OK button displayed on the examination parameter selection screen with the mouse).
In step 1004, the optical head 900 is moved to the initial alignment position.

  A screen for tomographic image imaging exemplified in FIG. 6A is displayed on the monitor 928. In this step, the anterior eye image and the fundus image are displayed. 2203 is an anterior eye image monitor, 2203a is an anterior eye image, and 2203b is a left / right selection button of the eye to be examined, which also has a function of displaying which eye is selected by brightness. Reference numeral 2201 denotes a fundus image, 2208a denotes a position of a B-scan image of a tomographic image preview described later, and 2208b denotes a tomographic imaging range selected in step 1003.

  In this step, the optical head 900 is moved to the measurement start position in accordance with the left and right sides of the eye to be examined, and an image of the anterior eye portion of the eye 107 to be examined is picked up by the anterior eye observation CCD 171. FIG. 3A shows an example of the image, and the center of the image (displayed at the intersection of the indices 2203c and 2203d) coincides with the optical axis of the measurement optical system of the optical head 900. With respect to the XY direction, the control unit moves the optical head 900 so that the center of the pupil 2203e serving as the initial adjustment target position coincides with the image center position. The optical head 900 and the center of the anterior ocular segment image need only be aligned relatively. Therefore, the optical head 900 functions as a relative position changing means for changing the relative positions of the anterior eye side and It is also possible to adopt a mode of moving. FIG. 3B shows an example of the anterior eye image after the movement, and the center of the pupil 2203e coincides with the image center. The Z direction is adjusted by moving the optical head 900 based on the size of a bright spot (not shown) projected on the anterior segment on the image. This adjusts the Z direction so that the size of the bright spot is minimized.

The position after alignment of the head part 200 in this step is the initial alignment position. The center of the pupil 2203e is extracted by image processing. FIG. 3B shows a case where the center of the anterior ocular segment image coincides with the optical axis of the optical head 900. However, the present invention is not limited to this mode. If the value is within a predetermined first predetermined range, the subsequent operation may be performed.
Thereafter, the process automatically proceeds to step 1005.

In step 1005, a tomographic image preview and image quality guide are displayed on the monitor 928. That is, after the position adjustment to the initial adjustment target position, the image evaluation index of the tomographic image is visualized and displayed on the monitor 928.
The personal computer 925 constructs a tomographic image at the position 2208a from the signal from the line sensor 182 and displays it on 2202 in FIG. An indicator 2205 displays a Q index value that is a guide for image quality of the displayed tomographic imaging preview image 2202. As this goes to the right, the Q index value of the image increases, and the image quality is visually shown. Here, the Q index is one of OCT image evaluation indexes, and indicates the ratio of pixels effective for diagnosis in the histogram of the image. A program for calculating the Q index and comparing it with a target value or a value at another alignment position is image comparison means in the present embodiment. This program is integrated with the above-described imaging program and is executed by the personal computer 925 which is an apparatus control unit.

The Q index calculation method is described in the following document.
[Literature] British Journal of Ophthalmology 2006; 90: P186-190 “A new quality assessment parameter for optical coherence tomography”

Here, the Q index value is used as a guide for image quality, but the following image evaluation indexes are also conceivable.
(1) SNR This is an index that is often used in the past, and indicates the ratio between the maximum value of the luminance value of the image and the luminance value of the background noise.
(2) Local image contrast A contrast obtained from the average luminance value of the local area in the retina and the average luminance value of the background. An example thereof will be described with reference to FIG. FIG. 4A shows a preview image of the tomographic image 2202. A1 is a partial area of the relatively dark ONL (outer granule layer) in the retinal layer. A2 is a partial region of the background portion. The contrast is calculated from the average luminance value of these two areas.

  The local contrast is not limited to the ONL and the background, but may be an interlayer required for diagnosis or a contrast between the layer and the background, and may be set so that the examiner can select.

This local image contrast calculation requires segmentation for recognizing a region by identifying ONL or the like.
In this step, the optical path length of the reference optical path is adjusted by moving the mirror 132-4, the fundus image is focused by the lens 135-3, and the tomographic image is focused by the lens 135-5. Although these are also automatically adjusted, as shown in FIG. 6A, the screen is provided with a gate position adjustment slider 2207 and a focus position adjustment slider 2208 so that the examiner can make fine adjustments after the automatic adjustment. ing.

Next, the process automatically proceeds to step 1006.
In step 1006, it is determined whether the Q index value, which is the image evaluation index value, exceeds a predetermined target value. If the image evaluation index value exceeds the target value, that is, if it is determined that the image is good, the process proceeds to step 1014. If the image evaluation index value is less than or equal to the target value, that is, if it is determined that the image is not good, the process proceeds to step 1007.
The operation for obtaining the image evaluation index value from the tomographic image exemplified above is executed by the area pointed out by the image evaluation means in the personal computer 925 which is the apparatus control unit.

  In step 1007, it is determined whether the number of repetitions of the alignment fine adjustment routine in steps 1006 to 1012 is larger than a set value. If the number of repetitions is larger than the set value, the process proceeds to step 1008, the target value of the image evaluation index is corrected downward, and the process returns to step 1006. This is because a high image evaluation index value may not be reached at any position depending on the eye to be examined, and the auto alignment operation is converged at that time. If the number of repetitions is less than or equal to the set value, the process proceeds to step 1009.

In step 1009, the personal computer 925 outputs a movement instruction to move the optical head 900 to the stage unit 950, and moves the optical head 900 to a new alignment position according to the movement amount designated in the movement instruction. That is, when it is determined that the positional deviation between the center position of the anterior ocular segment image and the optical axis of the optical head 900 is within the first predetermined range, the position to be the center of the anterior segment image in actual measurement Is designated as a new alignment position, which is a predetermined position, and the optical head 900 is relatively moved. In this operation, the specific area in the personal computer 925 functions as the specifying means of the present invention. Before moving, stop the anterior eye auto-alignment function.
Here, how to obtain a new alignment position will be described. For example, the tomographic image may be tilted on the screen. This will be described with reference to FIGS. 5A to 5C taking the case of macular vicinity imaging as an example.

  In FIG. 5A, when the visual axis of the eye 107 to be examined is not inclined with respect to the measurement light 105, when the macular center is imaged by fixation, the incident light and the macular vicinity of the retina 127 are nearly perpendicular. The intensity of the return light is large and a high signal intensity can be obtained. On the other hand, in the eye to be examined 107 whose visual axis is inclined, when the incident light 105 reaches the retina 127 as shown in FIG. At the same time, the tomographic image is often inclined as shown in FIG. At that time, the Q index, which is an image evaluation index, also has a low value. Here, the optical head 900 is moved by comparing the distances of the image ends of the RPE (pigment epithelium) layer having the highest luminance on the tomographic image by the above-described segmentation. In this case, the optical head 900 functions as tilt changing means in the present invention. In addition, when the optical head 900 changes this inclination, the specified position is specified by the specifying means in accordance with this change. The optical head 900 is moved so that the distance L1 at the left end from the upper left image top (gate position) to the RPE layer and the distance at the right end L2 in FIG. FIG. 4B shows an example after the movement, in which the optical head 900 is moved in the X direction by d from the initial alignment position. Incident light 105 is substantially perpendicularly incident on the vicinity of the macula, and L1 and L2 at both ends are approximately equal as shown in FIG. 4B. Under such conditions, the Q index value often increases.

  Here, an example is shown in which automatic tilt correction is performed based on the distance from the RPE layer from the upper part of the image. However, when attention is paid to NFL (nerve fiber layer) such as glaucoma examination, automatic correction is performed based on the distance from the upper part of the image to NFL. Tilt correction may be performed.

In the figure, although only the X direction is described, tilt correction may be performed with respect to X or Y, or both directions. In order to obtain movement in the Y direction, it is necessary to take a preview of a tomographic image that is a cross section in the Y direction.
In this state, the process automatically proceeds to step 1010.

  In step 1010, the image evaluation index value is compared with the value before the movement in step 1009 (previous value). If it is smaller than the previous value, the process proceeds to step 1011. If it is larger than the previous value, the process proceeds to step 1012.

  In step 1011, the optical head 900 is moved to the previous position. At this time, it may be changed in this step so as to apply a coefficient for weighting the calculated correction amount so that the movement amount does not become the same as the current movement amount. For example, a value obtained by multiplying the correction amount calculated from the inclination by a coefficient 0.5 may be used as the actual movement amount. Alternatively, since the image evaluation index may be lowered due to a factor other than the inclination, it may be set to move a predetermined step amount next time.

In step 1012, as explained in the above example, anterior eye auto-alignment is started at a position away from the pupil center by the distance d, that is, a new alignment position, and imaging is continued.
That is, the alignment position is moved to a new adjustment target position set by the movement of the optical head 900, and based on this, automatic alignment that is position adjustment is executed.
Thereby, it is possible to take an image while maintaining a good image obtained even in tomographic imaging having a relatively long imaging time. The distance d from the pupil center indicating the new alignment position is temporarily stored.

FIG. 3C shows an anterior eye image 2203a at that time. A mark 2203f indicating the new alignment position is displayed at a position separated from the center of the pupil 2203e by d to clearly indicate to the examiner that the alignment is continued at the new position. That is, the anterior eye image is displayed on the monitor 928, and the adjustment target position is further displayed on the anterior eye image. In the present invention, when the optical head 900, which is a relative position changing means, is moved to a new alignment position defined as an adjustment target position or a predetermined position, the amount of deviation between the predetermined position and the optical axis of the optical head 900 The alignment operation is performed so as to fall within the second predetermined range designated. Here, the predetermined position corresponds to a position designated as a predetermined position in the anterior segment image in advance. The second predetermined range may coincide with the first predetermined range described above, or may be set differently from the first predetermined range by resetting or specifying in advance. The above operations are executed by an area that functions as a control unit in the personal computer 925. Thereafter, the process automatically proceeds to step 1013.
In step 1013, the number of repetitions is incremented by 1, and the process returns to step 1006.
Then, step 1006 to step 1013 are repeated to finally move to step 1014.

  In step 1014, a tomographic image is taken with the scan pattern set in step 1003, and at the same time, the tomographic image is stored in a storage device in the personal computer 925. This saving operation may be performed automatically or by clicking the imaging button 2209 with a mouse. The process automatically proceeds to step 1015.

In step 1015, a screen for selecting whether to continue or end the examination is displayed, and the examiner selects one of them. Further, the captured tomographic image may be displayed at this stage. If the inspection is continued, the process proceeds to step 1016, the inspection parameter setting for the next imaging is performed, and the process returns to step 1006. If the inspection is completed, the process proceeds to step 1017 to end the inspection.
The above is the imaging flow in the fundus examination apparatus of the present embodiment.

  The new alignment position stored every time it is updated is stored in the hard disk 926 in the personal computer 925 as the adjustment target position for each subject together with the patient information when the tomographic image is stored. As a result, when inspecting the same eye, auto-alignment can be started from a state where the Q index value is high by starting auto-alignment using the new alignment position as the initial adjustment target position at the time of re-examination. Taking FIG. 5A as an example, auto-alignment can be started not from the center of the pupil but from a position away from the center of the pupil by the distance d, so the burden on the subject is reduced by shortening the examination time.

  Here, it has been described that the Q index value is improved by automatically correcting the inclination. However, in order to increase the Q index value, auto-alignment from another viewpoint is also conceivable. For example, auto alignment that avoids partial opacity of the lens due to cataracts can be mentioned.

  This will be described with reference to FIGS. 110 indicates partial turbidity. FIG. 5D shows a state where the positions of the eye to be examined 107 and the optical head 900 have been adjusted in step 1004. This shows a case where the partial turbidity 110 due to cataract is particularly in the center of the optical path, and the light beam 105 of the measurement light for tomographic imaging is scattered and hardly reaches the fundus 127. Therefore, the tomographic image preview image becomes very dark and at the same time the Q index value decreases. In this case, the new alignment position in step 1007 is a position moved by a predetermined step amount from the current position. For example, the optical head 900 is moved in the X or Y direction by about 0.5 mm as the distance d. This is repeated, and as a result, the optical head position becomes turbid 110 and the measurement light beam 105 for tomographic imaging can be guided to the fundus (FIG. 5E). Therefore, tomographic imaging can be performed at a position where the Q index value is high. Since auto-alignment can be continuously performed at a position where the turbidity is avoided, even in tomographic imaging with a relatively long imaging time, imaging can be performed while maintaining a good image. Further, since the automatic adjustment for finding a position to avoid turbidity basically takes more time than the inclination correction that can estimate the moving distance, it is more effective to reduce the time than the inclination correction by continuing the auto alignment.

As described above, a good tomographic layer can be automatically imaged, and auto alignment for obtaining the good tomographic image can be continuously performed.
From the point of view of the examiner, the use is simple, and from the point of view of the subject, the examination time is shortened and the burden is reduced.
That is, since the position where a good tomographic image can be captured can be found automatically, the operator's operation is further simplified.

In addition, the examiner can finely adjust the alignment position, and can search for a position where a good tomographic image can be captured more directly.
Further, by visualizing and displaying the image evaluation index of the tomographic image, the examiner can easily determine whether the tomographic image is good.

Further, by displaying the adjustment target position together with the anterior eye image, the examiner can easily confirm whether the alignment function is working effectively.
In addition, when saving tomographic images, the adjustment target position is saved for each subject, and when the subject information is called at the time of reexamination, the adjustment target position is recalled at the same time, and the initial adjustment target position at the time of reexamination is obtained. By doing so, the burden on the subject can be further reduced by shortening the alignment time during the re-examination.

[Example 2]
The fundus examination apparatus of the present invention differs from the first embodiment only in the tomographic imaging flow. Specifically, the examiner determines a good alignment position from the initial alignment position. Explanations other than the flow and the imaging operation screen are the same as those in the first embodiment.
Since the other apparatus configuration is the same, the description thereof is omitted.

(Tomographic imaging flow)
The imaging flowchart shown in FIG. 1B will be described in the order of steps.
FIG. 6B shows an operation screen for tomographic imaging of the present embodiment. The difference from the first embodiment is that the examiner includes an optical head moving button 2204 for operating the movement of the optical head 900.
Since Steps 3001 to 3005 are the same as Steps 1001 to 1005 of the first embodiment, a description thereof will be omitted.

  In step 3006, the examiner refers to the display of the tomographic image preview 2002 and the Q index value indicator 2205 in FIG. 6B to capture the tomographic image or perform initial alignment in order to obtain a better image quality. It is determined whether or not the optical head 900 is moved and adjusted from the state. When capturing a tomographic image, the imaging button 2209 is clicked with the mouse, and the flow proceeds to steps 3009 and 3010. On the other hand, when not imaging, the examiner gives an instruction to move the position of the optical head 900 in order to move and adjust the optical head 900 from the initial alignment state. Specifically, the optical head moving button 2204 is operated. For example, in the state of FIG. 4A, the left-hand movement button of the optical head movement button 2204 is clicked or held by the mouse. In that case, the process automatically proceeds to step 3007.

  In step 3007, the inclination of the tomographic image is corrected to the state shown in FIG. 4B by moving the optical head 400 in the positive direction of the x axis shown in FIG. At this time, the Q index value becomes high and is reflected in the indicator 2205. The process automatically proceeds to step 3008. Further, the alignment operation by the anterior eye is temporarily stopped before the optical head 900 is moved.

  In step 3008, each time the examiner performs an operation, the distance d from the initial alignment position is stored as a new alignment position, and the anterior eye alignment is restarted and maintained while the position is maintained. Then, the process returns to step 3006.

  The above steps 3006 to 3008 are repeated, and when the tomographic image becomes good, the examiner clicks the imaging button 2209 with the mouse, and the apparatus captures the tomographic image with the set scan pattern and the tomographic image captured by the personal computer 925. Save the image. Then, the process proceeds to step 3010 automatically.

Steps 3010, 3011, and 3012 are the same as those in the first embodiment and correspond to steps 1015, 1016, and 1017, respectively. Therefore, the description is omitted.
The above is the imaging flow of the present embodiment.

  Similar to the first embodiment, the new alignment position stored each time it is updated is stored in the storage device 926 in the personal computer 925 together with the patient information when the tomographic image is stored. As a result, when examining the same eye to be examined, fine adjustment by the examiner can be performed from the new alignment position, that is, the image quality of the tomographic image is relatively high, and the examination time at the reexamination can be shortened.

As described above, even when the examiner finely adjusts the alignment position of the optical head 900 in order to obtain a good tomographic image with respect to the eye to be examined, good auto-alignment with respect to the eye to be examined is possible.
Similarly to the first embodiment, the use is simple from the viewpoint of the examiner, and the examination time is shortened and the burden is reduced from the examinee.
Further, another example of the operation in steps 3006 and 3007 will be described.
The tilt of the tomographic image may be configured as shown in FIG. 6C so that the operation can be understood more intuitively than the operation of the optical head moving button 2204. In FIG. 6C, reference numeral 2211 denotes a movable mouse cursor that is operated by the examiner with a mouse and designates an instruction unit on the screen, and 2202a and 2202b denote tilt adjustment buttons. The tomographic image 2202 is displayed for the first time by positioning the mouse cursor 2211 in the vicinity of the tilt adjustment buttons 2202a and 2202b. For example, since the right end side of the tomographic image 2202 is raised, the user keeps clicking or holding the click. Based on the instruction, the optical head 900 is moved to lower the right end of the tomographic image. By performing this adjustment, it is possible to adjust to a tomographic image that the examiner considers preferable. Further, when this tilt adjustment operation is completed and the mouse cursor 2211 moves away from the vicinity of the tilt adjustment buttons 2202a and 2202b, they are not displayed so that information of tomographic images can be displayed on the entire screen.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

107 eye 200 eye fundus examination apparatus 900 optical head 925 personal computer 926 hard disk 928 monitor 950 stage unit 951 base unit 2202 tomographic image screen 2203a anterior eye image screen

Claims (10)

A head unit including a measurement optical system for guiding return light from the illuminated eye to be detected to the light receiving means;
Position changing means for changing a relative position between the head unit and the eye to be examined based on an inclination of a tomographic image of the eye to be examined acquired based on the return light;
An ophthalmologic apparatus comprising: The measurement optical system includes tomographic image acquisition means for acquiring a tomographic image of the eye to be examined.
The ophthalmic apparatus according to claim 1, wherein the position changing unit changes a relative position between the tomographic image acquisition unit and the eye to be examined so that an inclination of the tomographic image becomes small.   The ophthalmologic apparatus according to claim 1, wherein the inclination is obtained based on a position of a predetermined layer in the tomographic image.   The ophthalmologic apparatus according to claim 1, wherein the inclination is obtained based on a distance from each of two points in a predetermined layer of the tomographic image to a predetermined position.   5. The position changing unit changes a relative position between the head unit and the eye to be examined so that distances from two points on the predetermined layer to the predetermined position are equal. Ophthalmic equipment.   4. The ophthalmologic apparatus according to claim 3, wherein the predetermined layer is a retinal pigment epithelium layer or a nerve fiber layer.   The ophthalmologic apparatus according to claim 4, wherein the predetermined position is an upper end portion of a tomographic image.   8. The position changing unit according to claim 1, wherein the relative position between the head unit and the eye to be examined is changed by moving the head unit based on an inclination of the tomographic image. An ophthalmic device according to claim 1. A method for controlling an ophthalmologic apparatus including a head unit including a measurement optical system for guiding return light from an illuminated eye to be measured to a light receiving means,
A control method comprising a position changing step of changing a relative position between the head unit and the eye to be examined based on an inclination of a tomographic image of the eye to be examined acquired based on the return light.   A program for causing a computer to execute the steps of the control method according to claim 9.

Images